1. Field of the Invention
The present invention relates generally to coverings for architectural openings and more particularly to a Venetian blind type covering where the slats are fixed to the supporting ladder.
2. Description of the Relevant Art
Coverings for architectural openings have taken numerous forms over many centuries. Initially, fabrics were simply draped across architectural openings such as windows, doorways, archways, and the like. These early crude forms of coverings evolved into pleated draperies, curtains, and the like, which were made out of suitable fabrics for providing the desired aesthetic and utilitarian function desired. Venetian blinds are another popular form of covering for architectural openings wherein a plurality of horizontally disposed slats are supported on tape or cord ladders so as to be movable between an extended position wherein the slats are evenly distributed across the architectural opening and a retracted position wherein they are vertically stacked adjacent to the top of the opening. The slats are also tiltable or pivotable about a longitudinal horizontal axis between open and closed positions with flat surfaces of the slats lying horizontally in the open position defining spaces therebetween and somewhat vertically in the closed position so as to overlap and block vision through the blind. The slats are moved between the open and closed positions by shifting vertical runs of the ladder in opposite directions so as to tilt the rungs which interconnect the vertical runs of the ladder at vertically spaced locations and support the slats.
When tilting slats in conventional Venetian blinds between open and closed positions by tilting the rungs on which the slats are supported, the slats are typically pivoted about a longitudinal horizontal axis through slightly less then 90 degrees so that even though the slats overlap adjacent slats in their closed positions, there are gaps between the slats which permit the passage of light. The slats do not fully pivot through 90 degrees in as much as the lower edge of a slat, as it is being pivoted, is trapped in crotches between vertical runs and associated rungs on which the slats are supported.
In an effort to increase the blockage of light passing through a Venetian blind that has been closed by pivoting the slats into substantially vertical orientations, it would be desirable to more fully pivot the slats through or closely approaching 90 degrees but to date this has not been achievable with the use of conventional tape or cord ladders which have been in use for many years.
Attempts have been made, as evidenced by British specification No. 1,165,243, to better block the passage of light through the slats of a Venetian blind, but such attempts have aesthetic shortcomings. For example, in the system described in the British patent, the holes, which are typically found in the slats of Venetian blinds to accommodate the lift cords, have been removed with the lift cords being interwoven along the vertical runs of the cord ladders. In order to hold the slat in position, tabs are punched in the slats of the vertical blind, which are adapted to clamp the corresponding rungs of a cord ladder to prevent the slat from sliding relative to the cord ladder while permitting it to be removed without removing the lift cords. As will be appreciated, in such a system, the tabs are aesthetically displeasing as they are punched from the main body of the slat and thereby protrude from one surface of the slat and also allow light to pass through the punched hole behind the tab, which is undesirable.
Accordingly, the present invention has been developed to overcome the shortcomings in prior art blinds, shades, and the like, to provide a Venetian blind with improved light blockage when in its closed position, and to provide a new system for lifting blinds or shades at predetermined locations along their length in an aesthetically pleasing manner.
In accordance with one aspect of the present invention, a conventional ladder for use in a Venetian blind having a pair of vertical runs or guide cords and a plurality of vertically spaced rungs for supporting slats of the Venetian blind further includes an innocuous connector, such as adhesive, on each rung to connect the rung to a surface of an associated slat so that as the rung is tilted by opposite vertical movements of the guide cords, the associated slat is lifted by the rung so as to assume an orientation that is or is very nearly vertical.
Accordingly, when the Venetian blind is extended across an architectural opening and the slats, which have a smooth, hole free and substantially continuous surface, are tilted about their horizontal axes by opposite vertical movements of the guide cords, the slats are shifted from a substantially horizontal open position to a vertical or substantially vertical closed position. The width of each slat is greater than the spacing between adjacent rungs so that when the slats are substantially vertically positioned in the closed position of the blind, they overlap and are biased into engagement with the next adjacent slats to preclude the passage of light through the covering.
It will be appreciated with the description hereafter that the principles of the present invention can also be applied to vertical blinds, shutters, shades, and the like.
Other aspects, features, and details of the present invention can be more completely understood by reference to the following detailed description of the preferred embodiment, taken in conjunction with the drawings and from the appended claims.